Blue Needs Help!

[Blue_Runner]

I have a good buddy with an early 90's Yamaha 150. He recently had the same problem and was able to clean the jets and get it back up to par. He lives less than 2 miles from me so I will be calling him soon.

Ferm, explain what you mean by this:

Another thing you can try is to take it out and one at a time pull a plug wire off until you find the cylinder that doesn't change with the plug wire being off.